jonathan lloyd (majrmovies)sandiego.pm.org/presentations/oscon_2009.pdf · • zen and the art of...

OSCON 2009Jonathan Lloyd (majrmovies)

Who am I?

• I have been programming Perl for ~ 4 years

• I work for a small business (~ 30 employees) in Irvine, CA that does e-commerce and distribution.

• I do primarily web programming with Perl, mod_perl2, CGI and JavaScript. Including lots of web service communications like SOAP, XML, and JSON.

The Presentations• Perl 6 Update & Perl 6: What? Why? How? - Larry Wall & Damian Conway

• Distributed Applications with CouchDB - J Chris Anderson

• Open Source Language Roundtable

• Transparent Sharing of Complex Data with YAML - Ingy döt Net

• Zen and the Art of Abstraction Maintenance - Alex Martelli

• Gearman: Building a Distributed Platform - Eric Day and Brian Aker

• 7 Principles of Better API Design - Damian Conway

• Situation Normal, Everything Must Change - Simon Wardley









Disclaimer: I am not these people. I just listened to these people.









Disclaimer: I am not these people. I just listened to these people. And stole some of their materials for this presentation.






• Prism, Bringing Web Applications to the Desktop - Matthew Gertner




Perl: The Metrics

• Perl is 21 year’s old.

8

Perl: The Metrics


• Perl 5 is 14 years old.

Perl: The Metrics



• Larry Wall is 55 years old.

Perl: The Metrics



• Larry Wall is 55 years old.

• The idea of Perl 6 was introduced to the community on October 24th, 2000.

Perl 6: Why?

• We have 20 years of experience with the language.

Perl 6: Why?


• We have a much better Larry.

Perl 6: Why?



• We have Damian Conway

Perl 6: Why?



• We have Damian Conway

• “It’s time to steal all the good ideas from other languages.”

Perl 6: Seriously?Comments are inline-able

my $x# This is a comment to the end of the line

= 1;

use v5;

use v6;my $y #{ Need a better var name!} = 2;

Perl 6: Seriously?String lists

# throw some strings in to an arraymy @names = qw(Jonathan David Lloyd);

# throw variables and strings -- no more qw!my @meals = ($breakfast, ‘Lunch’, ‘Dinner’);

use v5;

use v6;# The qw list constructor gets prettiermy @names = < Jonathan David Lloyd >;

# Interpolates variables or stringsmy @meals = << $breakfast Lunch Dinner >>;

my @names = <<

Jonathan # This is my first name>>

Perl 6: Seriously?Everything is an object

say keys %hash;say values %hash;

join(‘-’, $year, $month, $day);for (sort keys %hash) { say; }

use v5;

use v6;%hash.keys.say;

%hash.keys.sort.join(‘ | ‘);%hash.keys.reverse.join(‘-’).say;

.say for %hash.keys.sort;

Perl 6: Seriously?Variable declarations

my $variable = “String”;my $variable = 10;my $variable = new CGI;

my @array = (‘String’, 10, $object);

use v5;

use v6;my Str $variable = ‘a scalar’;my Int $variable = 10;

my Str @array = < Jonathan David Lloyd >;my Int @array = 1..10;

Perl 6: Seriously?Junctions

my @odds = qw(1 3 5 7 9);my @nums = qw(0 1 2 3 4 5 6 7 8 9);

for my $num (@nums) {if (grep $_ eq $num, @odds) {say “$num is odd”; ...

use v5;

use v6;for (@nums) {say “$_ is odd” if $_ == any (@odds);say “$_ in even” if $_ == none (@odds);

}

# The comparisons are performed in parallel!

Perl 6: Seriously?1. Strictures and

warnings on by default2. Comments are inline-

able3. Big revamp of POD4. Identifiers5. String lists6. Sigils sanitized7. Everything is an object8. Variable declarations9. State variables10.Constants11.Lists12.Generators13.Pairs14.Smarter string

interpolations15.Heredocs fixed16.Junctions17.Array indexing

18.Multidimensional arrays

19.Hash features20.Data-preserving hash

transformations21.Operator revamp22.DWIMier comparisons23.DWIMier matching24.Switch statements and

switch loops25.Defaulting operators26.IO27.Sort has been fixed28.Revamped loops29.Nested postfix control

statements30.Error variables31.Subroutines32.Named parameters

33.Parameter types and return types

34.Captures35.“Slurpy” parameters36.The MAIN subroutine37.Classes38.Inheritance39.Constructors and

destructors40.Multiple dispatch41.Roles42.Regular Expressions43.Named regexes44.Match-time variable

interpolation45.Named regexes and

grammars

Perl 6: How?

• Download “Rakudo”

• It won’t hurt your current distribution/system

• Use modules built for Perl5 that are similar to Perl6::*

Distributed Applications with CouchDB

• Document-oriented, not relational database.

• Schema-Free (JSON)

• RESTful HTTP API

• JavaScript Powered Map/Reduce Views

• N-Master Replication, Highly Concurrent, Robust Storage, Buzz word, Buzz word, Buzz word.


• Documents in the Real World

• Bills, letters, tax forms ..

• Same type != same structure

• Can be out of date

• No references

• Natural Data Behavior

• Document-oriented, not relational database.


{

"_id": "BCCD12CBB","_rev": "3-AB764C",

"type": "person","name": "Darth Vader","age": 63,"headware":["Helmet", "Sombrero"],"dark_side": true

}

• Schema-Free (JSON)

• Unique ID for each document

• Data structure can change on a per-document basis

• Limited only by the data structures available in JSON


Create HTTP PUT /db/mydocidRead HTTP GET /db/mydocidUpdate HTTP PUT /db/mydocidDelete HTTP DELETE /db/mydocid


JSON


• Javascript-Powered Map/Reduce Functions

MapDocuments

Reduce


• N-Master Replication, Highly Concurrent, Robust Storage ..

-d '{"source":"http://server/db","target":"db-replica"

}’

Pull

-d '{"source":"db-replica","target":"http://server/db"

}'

Push

-d '{"source":"http://server-one/db","target":"http://server-two/db"

}'

Remotescp

JSONJSON

Server

• Terrific Idea

• Leverage Apache for its strength -- distributing documents

• Use client-side JavaScript to manage and display documents

• Replication across multiple servers, or being downloadable to offline applications is very simple

Pros

Cons


• Security (HTTP DELETE /db -- Oops!)

• Using Perl would require a DBD::CouchDB plugin for sanity

• Writing queries/views is not practical in a small shop

• No direct interface -- runs as a daemon that is simply killed

• Very JavaScript oriented

Open Source Language RoundtableJava: Rod Johnson (SpringSource)Perl: Jim Brandt (Perl Foundation)PHP: Laura Thomason (Mozilla)Python: Alex Martelli (Google)Ruby: Brian Ford (Engine Yard)

• Most dynamic programming languages are inherently the same. Don’t hate.

• Perl is the best for shell scripting

• JavaScript is a dynamic language completely undervalued, but hugely important in web development (i.e. Google)

• Runs on the client-side

• AJAX has enabled more dynamic communication with the server

• Frameworks like Prototype, Dojo, Moo Tools, and jQuery make it easy

Transparent Sharing of Complex Data with YAMLby Ingy döt Net (Hackers, Inc)

• YAML (YAML Ain't Markup Language)

• JSON == YAML

• YAML =!~ JSON

• YAML can store objects

• YAML can be streamed

• YAML has implementations in 8 different languages -- more to come ...

---name: ingyage: oldweight: heavy# I should comment that I also# like pink, but don't tell anybody.favorite colors:

- red- green- blue

---- Clark Evans- Oren Ben-Kiki- Ingy döt Net...

Zen and the Art of Abstraction Maintenanceby Alex Martelli (Google)

• Everything is built on something.

• You build layers of abstraction (Perl modules)

• All layers of abstraction leak.

• Understand the layers surrounding your code.

Bringing Web Applications to the Desktopby Matthew Gertner

• The browser wasn’t designed for running applications -- but it is being used that way

• HTML5 is furthering this effort

• Offline Operation

• Local Data

• Worker Threads

• Prism allows you to spin a process (separate from the browser) and interact with the OS using JavaScript calls to the API

Build Your Own Distributed Platform in 3 Hours

• Gearman provides a distributed application framework

• Clients - Create jobs to be run and sends them to a job server.

• Workers - Register with a job server and grab jobs to run.

• Job Server - Coordinate the assignment from the client to the works, handle restarts.

• “Gearman, like managers, assign the tasks but do none of the work.”


• Not everything needs immediate attention

• E-mail notifications

• Certain DB updates

• RSS indexing

• Search indexing Image Processing


• Background tasks

• Foreground tasks

• Asynchronous tasks

• No single point of failure (multiple job servers, multiple workers)

• Workers can be specific to certain jobs


• Written in C

• Perl API on CPAN (Gearman::XS)

• Command line tool

• Multi-language - mix client and workers

• Synchronous and Asynchronous queues

• Runs as a daemon (gearmand)

• Developing improved monitoring (statistics, configuration management, etc.)

• Only accepts a single string / file handle from Client to Worker

• Failure by worker -- not enough configuration (would rather it be function specific)

Pros Cons

7 Principles of Better API Designby Damian Conway

1.Do one thing really well

# read a file in to a variablemy $text = do { local (@ARGV, $/) = filename; <> };

use Perl6::Slurp;

my $text = slurp $fh;my $text2 = slurp ‘filename’;


2.Design by coding (work backwards)

# regex for floating point integermy $input =~ /([+-]?(?:\d+[.]?\d*|[.]\d+(?:[eE][+-]?\d+)?)/;

use Regexp::Common;my $input =~ /($RE{num}{real})/;my $input2 =~ /($RE{num}{int})/;my $input3 =~ /($RE{num})/;


3.Evolve by Subtraction

use IO::Prompt;while (prompt “next: “, -bool, -chomped) { print “You said ‘$_’\n”;}

while (prompt “next: “) { # autodetect, autochomp print “You said ‘$_’\n”;}


4.Declarative beats imperative

use Getopt::Euclid;

for my $x (0 .. $ARGV{-size}{h} - 1) { for my $y (0 .. $ARGV{-size}{w} - 1) { do_something_with($x, $y); }}

__END__

= item -s[ize]=<h>x<w>

Specify size of simulation

=for Euclid:h.type: int > 0h.default: 24w.type: int >= 10w.default: 80


5.Preserve the metadata

use Config::Std;

read_config $file_name => my %config;# update %config herewrite_config %config => $file_name;

read_config $file_name => my %config;# update %config herewrite_config %config;

bash> cd /home/jlloydbash> lsbash> cd docs/bash> lsbash> cd modules/bash> lsYou have typed the commands “cd [path] ls” 3 times, would you like to create an alias? [y|n]


6.Leverage the familiar

use Log::Log4perl;Log::Log4perl->init($log_config_file);

my $logger = Log::Log4perl->get_logger(__PACKAGE__);

$logger->debug(‘this is a debug message’);$logger->info(‘this is an info message’);$logger->warn(‘this is a warning message’);$logger->error(‘this is an error message’);$logger->fatal(‘this is a fatal message’);

use Log::StdLog { file => $log_file };print STDLOG debug => ‘this is a debug message’;print STDLOG info => ‘this is an info message’;print STDLOG warn => ‘this is a warning message’;print STDLOG error => ‘this is an error message’;print STDLOG fatal => ‘this is a fatal message’;


7.The best code is no code at all

my $obj = MyClass->new(‘data’);print $obj;

MyClass=HASH[0x12a8f2];

my $obj = MyClass->new(‘data’);

use Object::Dumper;print $obj;

Situation Normal, Everything Must Changeby Simon Wardley

• All good innovations undergo a process of commoditization


• All good innovations undergo a process of commoditization (i.e. Electricity)



• This trend can be mapped and seen in the market



• This trend can be mapped and seen in the market (i.e. CRM)



• This trend can be mapped and seen in the market (i.e. CRM)

• Competitive disadvantage to companies that fail to follow the market


• Economies of scale

• Pay per use

• Speed to market

• Focus on core

• Price competition

• Not “locked-in”

• Secondary sourcing

Pros

• Management of data/applications (different way of thinking/designing)

• Trust / Security

Cons

Thanks!Questions?